21201121000000 has 98 divisors (see below), whose sum is σ = 52588047450314. Its totient is φ = 8480448000000.

The previous prime is 21201120999991. The next prime is 21201121000001. The reversal of 21201121000000 is 12110212.

It can be written as a sum of positive squares in 7 ways, for example, as 19339730108416 + 1861390891584 = 4397696^2 + 1364328^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21201121000001) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 9600561 + ... + 11600560.

Almost surely, 2^{21201121000000} is an apocalyptic number.

21201121000000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201121000000 is an abundant number, since it is smaller than the sum of its proper divisors (31386926450314).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21201121000000 is an frugal number, since it uses more digits than its factorization.

21201121000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21201163 (or 21201128 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21201121000000 its reverse (12110212), we get a palindrome (21201133110212).

The spelling of 21201121000000 in words is "twenty-one trillion, two hundred one billion, one hundred twenty-one million", and thus it is an aban number.